Toroidal continuously variable transmission

ABSTRACT

A toroidal type continuously variable transmission in which a rolling member is arranged between a pair of rotary members with contacting its outer circumferential face with a rolling face of those rotary members being opposed to each other through an oil film, and in which a holding member for holding the rolling member in a rotatable condition is provided therewith, comprises: a lubricating oil feeding hole for spraying lubricating oil to a plurality of portions at the center side of the rotation of at least one of the end faces of said rolling member in an axial direction, which is arranged on said holding member.

TECHNICAL FIELD

[0001] This invention relates to a toroidal type (or traction type)continuously variable transmission which is constructed to vary the gearratio continuously by means of varying the torque transmitting pointbetween the rolling member and the rotary member in the radialdirection, with clamping a rolling member between a pair of rotarymembers to transmit a torque from one of the rotary member to the otherrotary member through the rolling member by rotating one of the rotarymember.

BACKGROUND ART

[0002] A continuously variable transmission of this kind is constructedwith, e.g., clamping a disc-shaped roller between a pair of discsarranged opposed to each other. The portion of the pair of discs wherethe outer side from a predetermined radius has an arcuate planecongruent with the arc centered on the center point of opposed planes ofthose discs, and such arcuate plane is leading to circumferentialdirection. The plane thus incurved three-dimensionally is a toroidalplane. The toroidal plane functions as a rolling face and the roller isclamped therebetween. The roller is a disc-shaped member and itssectional figure along in-depth direction of the outer circumferentialportion is congruent with the arcuate figure of the rolling face of thediscs. Accordingly, the roller is rotated by means of rotating one ofthe discs, and the other disc rotates sequentially. Then, the roller isinclined to move the radial position of the contact portion against oneof the discs, i.e., the radial position from the center axis of the discoutward, and also to move the radial position of the contact portionagainst the other disc to inner circumferential side, so that the speedchange ratio corresponding to the proportion of the radii of eachcontact portions is thereby set.

[0003] The amount of the torque to be transmitted by the toroidal typecontinuously variable transmission of this kind is varied in accordancewith the load to clamp the rollers by the discs. The bigger so-calledclamping force of the discs for clamping the roller becomes, the morethe transmittable torque increases pro rata. Also, in the toroidal typecontinuously variable transmission, transmission of the torque isexecuted with forming an oil film between the disc and the roller, andwith utilizing a sharing force of the oil film. Therefore, the biggerthe torque to be transmitted between the disc and the roller is, thebigger the shearing force of the oil film becomes. Accordingly, theamount of heat is increased at the torque transmitting portion.

[0004] Generally, a material of above mentioned discs and rollers is ametal, and a treatment to increase surface hardness is applied on thosediscs and rollers, however, mechanical characteristics of those such ashardness and abrasion resistance is deteriorated if a temperature isrisen when it is under operation due to above mentioned heat generation.In this connection, there is provided a device, which is constructed toexecute cooling with forming an oil film by means of sprayinglubricating oil aggressively to the outer circumferential face of theroller, and feeding the lubricating oil by rotating the roller to theboundary face where the disc and roller are contacted, is disclosed inJapanese Patent Laid-Open 2000-507667 as a prior art. According to theprior art disclosed in the above-mentioned Laid-Open, the oil film maybe formed between the roller and the disc with transporting thelubricating oil blown to the outer circumferential face of the roller tothe contact portion with the disc, by means of rotating the roller.Accordingly, a plenty of lubricating oil contacts with the outercircumferential face of the roller, and cooling of the contact portionbetween the roller and the disc may be thereby executed. However, ingeneral, temperature rise becomes problematic when the roller isrotating in high speed. Accordingly, most of the lubricating oil is easyto be scattered immediately due to centrifugal force even if thelubricating oil is blown to the outer circumferential face of theroller, as disclosed in the above-mentioned Laid-Open. Therefore, amountof the lubricating oil to be fed to the disc is not exactly sufficientand so that there is a disadvantage on the torque transmitting capacityto be limited because of insufficient cooling of the disc.

[0005] This invention has been made in the view of the aforementionedtechnical problem, and its object is to provide a toroidal typecontinuously variable transmission, which has an excellent coolingeffect.

DISCLOSURE OF THE INVENTION

[0006] In order to achieve the aforementioned objective, the presentinvention is characterized by providing a structure for radiating a heaton a portion where is not directory involved in transmitting a torque ataforementioned rotary members such as discs or rollers. Morespecifically, according to the present invention, there is provided atoroidal type continuously variable transmission in which a rollingmember is arranged in between a pair of rotary members with contactingits outer circumferential face with a rolling face of those rotarymembers being opposed to each other through an oil film, and in which aholding member for holding the rolling member in a rotatable conditionis provided therewith, is characterized in that: a lubricating oilfeeding hole for spraying lubricating oil to a plurality of portions atthe center side of the rotation of at least one of the end faces of saidrolling member in an axial direction is provided on said holding member.

[0007] According to the present invention, therefore, the rolling membercontacting with the rolling face of the rotary members through the oilface is rotated by means of rotating one of the rotary members, which isclamping the rolling member. Then, the torque is transmitted from therolling member to the other rotary member through the oil film, so thatthe torque is transmitted from one of the rotary member to the otherrotary member after all. In this case, radii of the contact positions ofthe rolling member against each rotary member are differed when therolling member is inclined against the center axis of the rotation ofthe rotary members, and the speed change ratio corresponding to theproportion of the radii is thereby set. And the lubricating oil is blownto the plurality of portions at the center side of the rotation of atleast one of the end faces of the rolling member in the axial directionfrom the feeding hole of the holding member. The lubricating oil flowswith spreading all over the end face by means of the rotation of therolling member, and cools the rolling member with drawing a heat fromthe rolling member in the meantime.

[0008] Also, according to the present invention, there is provided acontinuously variable transmission; in which a rolling member isarranged between a pair of rotary members with contacting its outercircumferential face with a rolling face of those rotary members beingopposed to each other through an oil film; in which a holding member forholding the rolling member in a rotatable condition is providedtherewith; and in which the lubricating oil is fed to the rolling memberheld by the holding member in the rotatable condition, is characterizedin that: the holding member comprises a circular plate for covering themost part of at least one of the end face of the rolling member in theaxial direction, with being opposed to said end face.

[0009] With this construction, therefore, the speed change ratio is setas the predetermined value, by means of transmitting the torque from oneof the rotary member to the other rotary member through the rollingmember, and inclining the rolling member against the center axis ofrotation of the rotary member. The lubricating oil is fed to the rollingmember, whereas at least one of the end faces of the rolling member inthe axial direction is covered by the circular plate portion of theholding member. Accordingly, the lubricating oil is kept in saturatingcondition between the rolling member and the rotary member.Consequently, the rolling member is cooled by the lubricating oilconserved on the end face side of the rolling member with drawing theheat.

[0010] Moreover, according to the present invention, a seal member forforming an oil reservoir between the circular plate portion and the endface of the rolling member in the axial direction may be arranged on theouter circumferential portion of the circular plate portion.

[0011] With this construction, accordingly, the oil reservoir is formedon the side of at least one of the end faces of the rolling member inthe axial direction, and the rolling member is cooled by the lubricatingoil saturated therein.

[0012] Furthermore, according to the present invention, there isprovided a toroidal type continuously variable transmission in which arolling member is arranged between a pair of rotary members withcontacting its outer circumferential face to a rolling face of thoserotary members being opposed to each other through an oil film; and inwhich a holding member for holding the rolling member in a rotatablecondition is provided therewith, is characterized in that: aconcavo-convex portion is formed on at least one of the end faces of therolling member.

[0013] The concavo-convex portion may function as a fin for radiatingthe heat.

[0014] With this construction, therefore, the speed change ratio is setas the predetermined value by means of transmitting the torque from oneof the rotary member to the other rotary member through the rollingmember, and inclining the rolling member against the center axis ofrotation of the rotary member. Heat radiation from one of the end facesof the rolling member to the air or to the lubricating oil is expeditedby means of the concavo-convex portion or the fins. As a result, therolling member is thereby cooled aggressively.

[0015] Also, above-mentioned concavo-convex portion may be microprojections for making a flow of the lubricating oil turbulent.

[0016] With this construction, accordingly, the flow of the lubricatingoil generated as a result of the rotation of the rolling member is madeturbulent flow by means of the micro projections. Consequently, heatconductivity from the rolling member to the lubricating oil becomesbigger and the rolling member is therefore cooled aggressively by thelubricating oil.

[0017] Still moreover, black body finishing to expedite heat radiationmay be applied to the surface of the rotary member or the rollingmember.

[0018] With this construction, therefore, heat dissipation from thesurface of the rotary member or the rolling member is generatedaggressively, and as a result, cooling of the rotary member or therolling member is expedited, and the temperature rise of those isthereby prevented or suppressed.

[0019] On the other hand, according to the present invention, there isprovided a continuously variable transmission; in which a rolling memberis arranged between a pair of rotary members with contacting its outercircumferential face with a rolling face of those rotary members beingopposed to each other through an oil film; and in which a holding memberfor holding the rolling member in a rotatable condition is providedtherewith, is characterized in that: fins for radiating the heat areformed on any portion of the rolling member other than the rolling face.

[0020] With this construction, therefore, the speed change ratio is setas the predetermined value by means of transmitting the torque from oneof the rotary member to the other rotary member through the rollingmember, and inclining the rolling member against the center axis ofrotation of the rotary member. The rotary member contacts with thelubricating oil or the ambient air with generating a flowage relatively,by means of its rotation. In this case, the heat transfer from therolling member to the ambient air or the lubricating oil is expedited bythe fins, and as a result, the rotary member is thereby cooledaggressively.

[0021] Still moreover, according to the present invention, there isprovided a toroidal type continuously variable transmission; in which arolling member is arranged between a pair of rotary members withcontacting its outer circumferential face to a rolling face of thoserotary members being opposed to each other through an oil film; and inwhich a holding member for holding the rolling member in a rotatablecondition is provided therewith, is characterized in that: an oilpassage for feeding the lubricating oil to the opposite side of therolling face of the rotary member is provided; and micro projections formaking the flow of the lubricating oil turbulent are formed on the faceto which the lubricating oil is to be fed.

[0022] With this construction, therefore, the speed change ratio is setas the predetermined value by means of transmitting the torque from oneof the rotary member to the other rotary member through the rollingmember, and inclining the rolling member against the center axis ofrotation of the rotary member. The lubricating oil is fed to theopposite side i.e., back side of the rolling face of the rotary member,and flown to the outer circumferential side of the rotary member bymeans of centrifugal force generated from the rotation. In this case,the flow of the lubricating oil becomes turbulent by the microprojections formed on the back face of the rotary member. As a result,the heat conductivity between the rotary member and the lubricating oilbecomes bigger, and the rotary member is thereby cooled aggressively bythe lubricating oil.

BRIEF DESCRIPTION OF THE DRAWING

[0023]FIG. 1 is a drawing showing one example of a power roller in acontinuously variable transmission according to this invention, and (A)is a plane view, (B) is a sectional view;

[0024]FIG. 2 is a sectional view showing another example of the powerroller in a continuously variable transmission according to thisinvention;

[0025]FIG. 3 is a side sectional view showing an example of the powerroller with fins formed thereon which is usable for a continuouslyvariable transmission according to this invention;

[0026]FIG. 4 is a side sectional view showing an example of the powerroller with micro projections which is usable for a continuouslyvariable transmission according to this invention;

[0027]FIG. 5 is a side sectional view showing an example of a disc withfins which is usable for a continuously variable transmission accordingto this invention;

[0028]FIG. 6 is a side view showing an example of a disc with microprojections which is usable for a continuously variable transmissionaccording to this invention;

[0029]FIG. 7 is a side sectional view showing an example of a disc inwhich a cover is mounted on its backside;

[0030]FIG. 8 is a side sectional view showing an example of an hydraulicchamber formed with mounting a cover on the backside of the disc; and

[0031]FIG. 9 is a typical side sectional view showing one example ofentire construction of a continuously variable transmission according tothis invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0032] Next, this invention will be described in connection with aspecific embodiment shown in the drawings. First of all, to describe oneexample of a toroidal type continuously variable transmission subjectedto this invention, a double cavity type full toroidal type continuouslyvariable transmission 1 is depicted typically in FIG. 9. In the toroidaltype continuously variable transmission 1, a pair of input discs 2 arearranged in so-called back-to-back relation each other, and a pair ofoutput discs 3 are arranged to be opposed to those input discs 2,namely, with sandwiching those input discs 2.

[0033] Those discs 2 and 3 are made such that portions of their opposedfaces on an outer circumference side from a predetermined radius areshaped, as cut in a plane on the center axis, to have a section of anarcuate plane of a predetermined radius, likewise the discs of thetoroidal type continuously variable transmission according to the priorart. And a power roller (a rolling member) 4, which corresponds to anidling member or a transmission member is sandwiched between rollingfaces 2B and 3B which are formed into such arcuate plane. That is, theoutput disc 3 in the right hand side of FIG. 9 is fixed in the axialdirection, and a hydraulic chamber 5 is arranged in the backside(opposite side of the rolling face 2B and 3B) of the output disc 3 inthe left hand side. And the power roller 4 is clamped by each of theinput discs 2 and the output discs 3 by means of feeding the oilpressure according to the torque to be transmitted to the hydraulicchamber 5. Namely, it is constructed to generate the clamping force forclamping the power roller 4 by each discs 2 and 3 from the oil pressureto be fed to the hydraulic chamber 5.

[0034] Here, each output discs 3 is connected to rotate integrally by anoutput shaft 6 arranged along the center axis of those discs, and theoutput shaft 6 penetrates center portions of each input discs 2.

[0035] Also, a bearing 7 is arranged between each input discs 2 andoutput shaft 6, and those input discs 2 and the output shaft 6 areconstructed to rotate relatively.

[0036] Also, an input shaft 8 is arranged rotatably in parallel with theoutput shaft 6. The input shaft 8 is slightly longer than the entirelength of the continuously variable transmission 1, and gears 9, 10 and11 are installed on three places in total such as its both front andrear end portions, and its intermediate portion.

[0037] The gear 10 at the intermediate portion is engaged with a gear 12integrated with said each input discs 2. Accordingly, the torque isinputted to the continuously variable transmission 1 from the inputshaft 8 through those gears 10 and 12.

[0038] Moreover, said power roller 4 is a disc-shaped member, and theouter circumference of which has a sectional shape formed into a curvedface with the curvature equal to the arc of the rolling face 2B and 3Bof each discs 2 and 3. The power roller 4 is inclined with respect tothe individual discs 2 and 3; therefore, radial portions of the contactportions between the power roller 4 and the discs 2 and 3 arearbitrarily changed. Three power rollers 4 are arranged between eachinput discs 2 and output discs 3 at even intervals, and six powerrollers are provided all together for the continuously variabletransmission 1 as a whole.

[0039] Furthermore, each power roller 4 is held rotatably and inclinablyby a carriage 13 which functions as a holding member. This carriage 13has a lubricating oil passage formed for feeding the lubricating oil tothe outer circumferential face of the power roller 4, as mentionedbelow.

[0040] Besides, an input gear 14 engaged with the gear 9 installed onthe input shaft 8 is provided, and the input gear 14 is rotated by themotive energy of a power source such as an engine (not shown).

[0041] One example of the power roller 4 and the carriage 13 is depictedin (A) and (B) of FIG. 1. The carriage 13 shown therein comprises a pairof circular plates 131 which has a diameter slightly smaller than thepower roller 4. Two portions of each circular plate 131 opposing eachother in the diametrical parallel are protruded outside of the outerdiameter of the power roller 4, and formed into butt portions 132 withleading to the side of the face being opposed to each other. Eachcircular plates 131 are assembled integrally with butting the buttportions 132, and as a result, a space which is little bit thicker thanthe power roller 4 is formed between those circular plates 131 toaccommodate the power roller 4 therein. More specifically, the powerroller 4 comprises a shaft portion 41 on its center portion, and theshaft portion 41 is held in a rotatable condition by a bearing 133 whichis mounted on the center portion of each circular plate 131.Consequently, the power roller 4 is held by the carriage 13 in arotatable condition.

[0042] A stem 134 as a shaft shaped member is mounted on one of the buttportions 132. This stem 134 is connected with a linear acting typeactuator such as a hydraulic cylinder (not shown) in an oscilatablecondition. The power roller 4 which is clamped by each discs 2 and 3 ismoved by the actuator backward and forward, and the power roller 4 isinclined against the center axis of rotation of each discs 2 and 3 inconsequence.

[0043] Also, an oil passage 135 is formed along the center axis of thestem 134. An end portion of the oil passage 135 of the actuator side iscommunicated with not shown hydraulic feeding unit. And another oilpassage 136 to be communicated with the oil passage 135 is formed ineach circular plate 131. Namely, the oil passage 136 penetrating thecircular plate 131 is formed from one of the butt portion 132 to theother butt portion 132, and the oil passage 136 at each circular plate131 is opened to the butt face.

[0044] Accordingly, as shown in FIG. 1, the oil passage 136 at upper andlower circular plates 131 are communicated each other at the buttportion 132. And the oil passage 135 at the stem 134 is communicatedwith the oil passage 136 of the circular plate 131 side in consequenceof connecting the stem 134 with one of the butt portions 132. Besides,the oil passage 136 at each circular plate 131 is formed as a loop inorder to compass the outer circumference of each bearing 133. That is,it is constructed to feed the lubricating oil to the bearing 133.

[0045] A lubricating oil spraying nozzle 137 to be communicated with theoil passage 136 is formed on each butt portion 132 with opening to theouter circumferential face of the power roller 4. Also, a plurality oflubricating oil feeding holes 138 for feeding the lubricating oil to theend face of the power roller 4 in the axial direction, i.e., to an upperface and a lower face in FIG. 1 is formed in the vicinity of the centerportion of each circular plate 131 with being communicated with the oilpassage 136 at each circular plate 131. Besides, the lubricating oilfeeding hole 138 may be formed into a plurality of pinhole shaped holes,otherwise, may be formed into narrow slit shape in order to let thelubricating oil spurt in film shape. Accordingly, the lubricating oil isfed to the bearing 133 simultaneously with being spurted to the outercircumferential face and both upper and lower face of the power roller4, by means of feeding the lubricating oil to the oil passage 136 ateach circular plate 131 through the oil passage 135 of the stem 134.

[0046] In the aforementioned continuously variable transmission 1, atorque is transmitted to the input disc 2 by means of rotating the inputgear 14 by not shown power source such as an engine or the like, throughthe gear 9 engaged with the input gear 14 and the input shaft 8. Thepower roller 4 contacting with the rolling face 2B through the oil filmis rotated when the input disc 2 rotates, and the output disc 3 isrotated subsequently, because the power roller 4 contacts with therolling face 3B of the output disc 3 through the oil film. As a result,the output shaft 6 integrated with the output disc 3 is thereforerotated.

[0047] In this case, the number of revolutions of the power roller 4 isdetermined depending on the number of revolutions of the input disc 2and the radius from the center of rotation at the contact portion withits rolling face 2B. Also, the number of revolutions of the output disc3 is determined depending on the number of revolutions of the powerroller 4 and the radius from the center of rotation at the contactportion of the power roller 4 with the rolling face 3B. Accordingly, thenumber of relative rotations of the output disc 3 to the input disc 2 isdetermined in connection with the radial position of the contactportions of the power roller 4 against each rolling faces 2B and 3B, andspeed change ratio is changed continuously by means of varying thecontact portions of the power roller 4 against each rolling faces 2B and3B by inclining the power roller 4 to the center axis of the outputshaft 6.

[0048] The lubricating oil is being fed to the carriage 13 through theoil passage 135 of the stem 134, when the continuously variabletransmission 1 is thus under operation. Accordingly, the lubricating oilis fed to the oil passage 136 of each circular plate 131 with beingpressurized, and the lubricating oil is spurt from the lubricating oilspraying nozzle 137 to the outer circumferential face of the powerroller 4 in consequence. The lubricating oil thus adhered on thecircumferential face of the power roller 4 is transported to the contactportions against each discs 2 and 3 by means of rotation of the powerroller 4, and forms an oil film mainly therebetween. And thetransmission of the torque is executed among the power roller 4 and eachdiscs 2 and 3 with utilizing a shearing force of the oil film. Also, apart of the lubricating oil spurt in the power roller 4 is scattered bya centrifugal force, 6 however, the lubricating oil draws a heat formthe power roller 4 and the power roller 4 is thereby cooled.

[0049] Also, the lubricating oil fed to the oil passage 136 is spurtfrom the lubricating oil spraying hole 138 to the portion near thecenter of rotation of the power roller 4. The lubricating oil is flownto the outer circumferential side of upper and lower face of the powerroller 4 by the centrifugal force generated from the rotation, andspread to all over those faces. Especially, in the aforementionedcontinuously variable transmission 1, both upper and lower face of thepower roller 4 is covered with the circular plate 131 and it is not theabsolute open space, therefore, the lubricating oil spurt from thelubricating oil feeding hole 138 is aggressively daubed onto both upperand lower face of the power roller 4. Consequently, the contacting areabetween the power roller 4 and the lubricating oil becomes larger, andthe heat transfer from the power roller 4 to the lubricating oil isthereby expedited. Accordingly, the power roller 4 is cooledaggressively.

[0050] Namely, the power roller 4 is cooled efficiently because thelubricating oil spurt from the lubricating oil feeding hole 138 spreadsto both upper and lower faces of the power roller 4 and draws the heatfrom the power roller 4, and because the lubricating oil is thrown offfrom the outer circumference of the power roller 4 by the centrifugalforce. Moreover, the lubricating oil is partially drizzled over therolling faces 2B and 3B of each discs 2 and 3, therefore, each discs 2and 3 is cooled by the lubricating oil with its heat being drawn.

[0051] Aforementioned continuously variable transmission 1 isconstructed to feed the lubricating oil to the end face of the powerroller 4 in the axial direction, i.e., the upper face or the lower facein FIG. 1, from a plurality of portions. Therefore, it is possible tofeed the film shaped lubricating oil to the upper face or the lower faceof the power roller 4 entirely with diffusing, as a result, heatconductivity between the power roller 4 and the lubricating oil isthereby improved and the power roller 4 is cooled efficiently. Moreover,the upper face or the lower face of the power roller 4 is covered withthe circular plate 131 of the carriage 13; therefore, it is possible tokeep the lubricating oil staying in the upper face side or the lowerface side of the power roller 4. Consequently, the heat conductivitybetween the power roller 4 and the lubricating oil is improved and thepower roller 4 is thereby cooled efficiently.

[0052] As described above, if the lubricating oil is kept in between thepower roller 4 and the circular plate 131, contact between the powerroller 4 and the circular plate 131 is facilitated the power roller 4may be cooled efficiently. Accordingly, it may also be constructed toform an oil reservoir between the power roller 4 and the carriage 13 inorder to conserve the lubricating oil. An example is shown in FIG. 2.

[0053] The example shown therein is the example of providing a sealmember 139 for sealing the space between the circular plate 131 and thepower roller 4 liquid tightly, on the outer circumferential side of thecircular plate 131 opposing to the power roller 4. That is, the sealmember 139 is installed on the carriage 13, and contacts with the upperface or the lower face of the power roller 4 with scraping. Accordingly,the lubricating oil spurt from aforementioned lubricating oil feedinghole 138 flows on the upper face or the lower face of the power roller 4and spreads to the outer circumferential side, however, the oilreservoir is generated on the portion of inner circumferential side fromthe seal member 139, because the flow is arrested by the seal member139. As a result, most part of the power roller 4 is covered with thelubricating oil and its heat is drawn by the lubricating oil, therefore,the power roller 4 may be cooled efficiently.

[0054] Besides, if the lubricating oil completely remains in the oilreservoir of inner circumferential side from the seal member 139, atemperature becomes higher gradually and no more cooling action isgenerated. Therefore, in order to avoid such disadvantage, it ispreferable to generate the flowage of the lubricating oil on both upperand lower sides of the power roller 4 with leaking the lubricating oilsequentially by means of forming a notch portion on a portion of theseal member 139, or by means of forming a through hole on the circularplate 131.

[0055] Cooling of the power roller 4 is executed with radiating the heatto the lubricating oil or the ambient air as mentioned above, therefore,it is preferable to form concavo-convex portions on the surface of thepower roller 4 in order to enhance the cooling action. One example offorming a fin 15 for enlarging the heat radiating area is shown in FIG.3, as an example of the concavo-convex portions. A plurality of thinfins 15 is formed on both upper and lower faces of the power roller 4shown in FIG. 3. The fins 15 may be formed into a ring shape, a spiralshape, or an appropriate shape arranged at certain intervals such as anarcuate shape.

[0056] Aforementioned fins 15 may be held by the carriage 13 which hasthe circular plate 131, as shown in FIG. 1 or FIG. 2, because theirfunction is to enlarge the heat radiating area against the ambientlubricating oil and air. Otherwise, the power roller 4 shown in FIG. 3may also be held by a carriage according to the prior art which isconstructed of a pair of rectangular plate shaped member, in lieu of thecarriage 13. Namely, the amount of the heat radiation by the fins 15 isenhanced and the power roller 4 may be cooled efficiently, even if inthe case of cooling the power roller 4 with spraying the lubricating oilonly to its outer circumferential face and exposing its both upper andlower face to the ambient air.

[0057] Another example of the concavo-convex portions is shown in FIG.4. The example shown therein is an example of cooling the power roller 4with the lubricating oil, and there are formed micro projections 16 formaking a flowage of the lubricating oil turbulent on both upper andlower face of the power roller 4. The micro projections 16 are sawtoothshaped projections as closed up in FIG. 4, such as, a face toward thecenter of the power roller 4 is vertical, and the face leading to theouter circumferential side from the vertical face is an inclined face toform a sectional triangle. Also, the ratio between a pitch p and aheight h (p/h) is set from 7 to 10. Besides, the micro projections 16may be arranged as a circularity formation in the circumferentialdirection, or may be arranged at certain intervals in thecircumferential direction and formed in alternate shifts in the radialdirection.

[0058] Also, the micro projections 16 may be formed into regularlyarranged projections by means of a mechanical processing such as cuttingor pressing. Otherwise, the micro projections 16 may be formed intoirregularly arranged projections by means of making surface of the powerroller 4 rough. In this case, the ratio between the pitch and the heightof the micro projections 16 is preferably around 10 to 13 in average.

[0059] It is preferable for the power roller 4 in which aforementionedmicro projections 16 are formed thereon to be used with being installedon the carriage 13 having the circular plate 131 as shown in FIGS. 1. or2., and the lubricating oil is fed to the portion at the center side ofthe rotation of both upper and lower faces when the torque istransmitted. And the lubricating oil is flown to the outercircumferential side by the centrifugal force generated from rotation ofthe power roller 4; however, the flowage of the lubricating oil is madeturbulent by means of the micro projections 16. As a result, heatconductivity between the surface of the power roller 4 and thelubricating oil becomes bigger, and the amount of the heat to betransmitted from the power roller 4 to the lubricating oil becomeslarger. Therefore, the power roller 4 is cooled efficiently.

[0060] In the toroidal type continuously variable transmission 1, asmentioned above, a heat is generated in consequence of transmission of atorque among the discs 2, 3 and the power roller 4, a temperature of thediscs 2 and 3 which is involved in the transmission of the torquebecomes accordingly higher. If a facial pressure and a temperature ofthe rolling faces 2B and 3B of the discs 2 and 3 become higher,durability and abrasion resistance is deteriorated. Therefore, it isdesirable to cool the discs 2 and 3 aggressively.

[0061] Both of cooling i.e., with the air or with the lubricating oilmay be employed in case of cooling the discs 2 and 3, likewise thecooling of the power roller 4 as mentioned above. As shown in FIG. 5, astructure wherein a number of thin plated fins 17 are formed on the backface i.e., opposite side of the rolling faces 2B and 3B may be employedas a structure for executing air-cooling. Besides, it is allowable forthe fins 17 to be formed into appropriate shapes such as ring shapedfins leading to the circumferential direction, or into arcuate shapedfines arranged intermittently in the circumferential direction.

[0062] Accordingly, the ambient air is flown relatively to the discs 2and 3 when the discs 2 and 3 in which the fins 17 are formed thereon arerotated, and the status becomes compulsory cooling with blowing air tothe fins 17. Consequently, discs 2 and 3 are cooled aggressively by theair from its backside face in connection with the enlargement of theheat radiating area resulted from providing of the fins 17. Therefore, atemperature rise is prevented or suppressed.

[0063] On the other hand, a construction for cooling with thelubricating oil is shown in FIG. 6. In the example shown therein, microprojections 18 are formed on the backside of the discs 2 and 3. Themicro projections 18 have a same kind of shape as that of theaforementioned micro projections 16 of the power roller 4 depicted inFIG. 4. A cross section in which a face toward the center of therotation of discs 2 and 3 is vertical and shaped into sawtooth shape,and the ratio between pitch p and height h (p/h) is set from 7 to 10.The micro projections 18 may be formed into regularly arrangedprojections by means of mechanical processing, otherwise, may be formedinto irregularly arranged projections by means of chemical treatment formaking surface roughness rough. Moreover, an oil passage 19 for spurtingthe lubricating oil to backside of the discs 2 and 3 is formed in anoutput shaft 6 which supports the discs 2 and 3.

[0064] According to the construction shown in FIG. 5, the lubricatingoil is spurted to the backside of the discs 2 and 3 from the oil passage19 when the discs 2 and 3 is rotated, and then, the lubricating oil isflown to the outer circumferential side by the centrifugal force inconnection with the rotation of the discs 2 and 3. The flowage of thelubricating oil is made turbulent on the surface where the lubricatingoil is to be flown, because there are formed the micro projections 18and surface is like a so-called rough face. Consequently, heatconductivity among the discs 2, 3 and the lubricating oil becomesbigger, and the heat generated as a result of transmission of the torqueis conducted to the lubricating oil aggressively. Accordingly, the discs2 and 3 are thereby cooled.

[0065] Besides, the amount of heat transfer between the lubricating oiland the discs 2, 3 becomes bigger if contacting time of those is long insome level. In this connection, for example, it is preferable to makethe contacting time of the lubricating oil and the discs 2, 3 longer insome measure, by means of installing a cover 21 which have a throughhole 20 on its outer circumferential portion with covering the backsideof the discs 2, 3, so as to conserve the lubricating oil spurted fromthe oil passage 19 inside of the cover 21, as depicted in FIG. 7. Also,as sown in FIG. 8, a hydraulic chamber 23 may be formed inside of thecover 21, by means of contacting an end portion of inner circumferentialside of the cover 21 with an outer circumferential face of a flangeportion 6A which is formed on the output shaft 6.

[0066] By the way, heat dissipation is generated in connection with heatradiation (heat emission) other than heat transfer. Therefore, blackbody finishing is applied to at least any one of the surface ofaforementioned discs 2, 3, power roller 4, or carriage 13, in order toincrease its emissivity. An appropriate method such as a heat treatmentor a coating treatment with a ceramic or a resin is sufficient for theblack body finishing. With this construction, the amount of heatdissipation in connection with heat radiation becomes larger inproportion as a temperature rise of the discs 2, 3 or the power roller4, therefore, the temperature rise of the discs 2, 3 and the powerroller 4 may be prevented or suppressed.

[0067] Here, this invention should not be limited to the specificembodiments thus far described, but it may also be applied to a singlecavity type full toroidal type continuously variable transmission, or toa half toroidal type continuously variable transmission. Moreover, inshort, it is sufficient for the fins for executing air cooling to beformed on the portion other than the rolling face, and it is alsopossible for the fins to be formed on the face of outer circumferentialside.

[0068] Here will be synthetically described the advantages to beattained by this invention. According to the present invention, as hasbeen described hereinbefore, the lubricating oil is spurted to aplurality of portions at the center side of the rotation of at least oneof the end face of the rolling member in the axial direction, from thefeeding hole of the holding member. The lubricating oil is flown withspreading all over the end face by means of the centrifugal force, andthe lubricating oil cools the rolling member with drawing a heat fromthe rolling member in the meantime. Accordingly, a temperature rise ofthe rolling members and the rotary members are prevented or suppressed,and as a result, a torque transmitting capacity of the continuouslyvariable transmission may be increased, and its durability may also beimproved.

[0069] Also, according to the present invention, at least one of the endfaces of the rolling member in the axial direction is covered with thecircular plate of the holding member and the lubricating oil is keptsaturated therebetween. Therefore, the rolling member is cooled by thelubricating oil conserved on the end face side of the rolling memberwith being drawn the heat. Accordingly, the temperature rise of therolling member and the rotary member are prevented or suppressed. As aresult, a torque transmitting capacity of the continuously variabletransmission may be increased, and its durability may also be improved.

[0070] Moreover, according to the present invention, the oil reservoiris formed with the seal member on at least one of the end faces of therolling member in the axial direction and the rolling member is cooledby the lubricating oil saturated therein. Accordingly, the temperaturerise of the rolling member and the rotary member is prevented orsuppressed. As a result, a torque transmitting capacity of thecontinuously variable transmission may be increased, and its durabilitymay also be improved.

[0071] Still moreover, according to the present invention, the heatradiation from at least one of the end faces of the rolling member inthe axial direction to the air or to the lubricating oil is expedited bythe fins, and the rolling member is cooled aggressively as a result.Accordingly, the temperature rise of the rolling member and the rotarymember is prevented or suppressed. As a result, a torque transmittingcapacity of the continuously variable transmission may be increased, andits durability may also be improved.

[0072] Also, according to the present invention, the flowage of thelubricating oil at the end face of the rolling member generated from itsrotation is made turbulent by the micro projections. Therefore, the heatconductivity from the rolling member to the lubricating oil becomesbigger, and the rolling member is cooled aggressively by the lubricatingoil. Accordingly, the temperature rise of the rolling member and therotary member is prevented or suppressed. As a result, a torquetransmitting capacity of the continuously variable transmission may beincreased, and its durability may also be improved.

[0073] Furthermore, according to the present invention, the black bodyfinishing for expediting the heat radiation is applied to the surface ofthe rolling member or the rotary member, so that the heat radiation isgenerated aggressively from the surface of the rolling member or therotary member. Therefore, the cooling of the rolling member or therotary member is expedited and the temperature rise of those isprevented or suppressed. Also, a torque transmitting capacity of thecontinuously variable transmission may be increased, and its durabilitymay also be improved.

[0074] On the other hand, according to the present invention, the rotarymember contacts with the ambient air or the lubricating oil withgenerating a flowage relatively by means of its rotation. In this case,the heat transfer from the rotary member to the ambient air or thelubricating oil is expedited by the fins, and as a result, the rotarymember is thereby cooled aggressively. Accordingly, the temperature riseof the rolling member and the rotary member is prevented or suppressed,so that a torque transmitting capacity of the continuously variabletransmission may be increased, and its durability may also be improved.

[0075] And according to the present invention, the lubricating oil isfed to the opposite side of the rolling face of the rotary member, i.e.,back face of the rotary member, and is flown to the outercircumferential side by means of the centrifugal force. In this case,the lubricating oil is made turbulent by the micro projections formed onback face of the rotary member, therefore, the heat conductivity betweenthe rotary member and the lubricating oil becomes bigger and the rotarymember is cooled aggressively by the lubricating oil. Accordingly, thetemperature rise of the rolling member and the rotary member isprevented or suppressed. As a result, a torque transmitting capacity ofthe continuously variable transmission may be increased, and itsdurability may also be improved.

[0076] Industrial Applicability

[0077] This invention can be utilized in the field for manufacturing thecontinuously variable transmission and in the field for using thecontinuously variable transmission. Especially, this invention can beutilized in the field relating to an automobile having the continuouslyvariable transmission mounted thereon.

1. A toroidal type continuously variable transmission, in which arolling member is arranged between a pair of rotary members withcontacting its outer circumferential face with a rolling face of thoserotary members being opposed to each other through an oil film, and inwhich a holding member for holding the rolling member in a rotatablecondition is provided therewith, characterized by comprising: alubricating oil feeding hole for spraying lubricating oil to a pluralityof portions at the center side of the rotation of at least one of theend faces of said rolling member in an axial direction, which isarranged on said holding member.
 2. A toroidal type continuouslyvariable transmission, in which a rolling member is arranged between apair of rotary members with contacting its outer circumferential facewith a rolling face of those rotary members being opposed to each otherthrough an oil film, in which a holding member for holding the rollingmember in a rotatable condition is provided therewith, and in whichlubricating oil is fed to said rolling member held by the holding memberin the rotatable condition, characterized by comprising: a circularplate for covering most part of at least one of the end face of saidrolling member in the axial direction with being opposed to said endface, which is provided on said holding member.
 3. A toroidal typecontinuously variable transmission according to claim 2, characterizedby further comprising: a seal member for forming an oil reservoirbetween the circular plate and the end face of said rolling member inthe axial direction, which is provided on the outer circumferentialportion of said circular plate.
 4. A toroidal type continuously variabletransmission, in which a rolling member is arranged between a pair ofrotary members with contacting its outer circumferential face with arolling face of those rotary members being opposed to each other throughan oil film, and in which a holding member for holding the rollingmember in a rotatable condition is provided therewith, characterized bycomprising: a concavo-convex portion which is formed at least one of theend face of said rolling member in the axial direction.
 5. A toroidaltype continuously variable transmission according to claim 4,characterized: in that said concavo-convex portion includes fins forradiating a heat.
 6. A toroidal type continuously variable transmissionaccording to claim 4, characterized: in that said concavo-convex portionincludes micro projections for making a flowage of the lubricating oilturbulent.
 7. A toroidal type continuously variable transmissionaccording to any of claims 1 to 6, characterized: in that a black bodyfinishing for expediting a heat radiation is applied to the surface ofsaid rotary member or the rolling member.
 8. A toroidal typecontinuously variable transmission, in which a rolling member isarranged between a pair of rotary members with contacting its outercircumferential face with a rolling face of those rotary members beingopposed to each other through an oil film, and in which a holding memberfor holding the rolling member in a rotatable condition is providedtherewith, characterized by comprising: fins for radiating a heat whichare formed on any portion of said rolling member other than said rollingface.
 9. A toroidal type continuously variable transmission, in which arolling member is arranged between a pair of rotary members withcontacting its outer circumferential face with a rolling face of thoserotary members being opposed to each other through an oil film, and inwhich a holding member for holding the rolling member in a rotatablecondition is provided therewith, characterized by comprising: an oilpassage for feeding the lubricating oil to the opposite face of saidrolling face of said rotary member; and micro projections for making theflowage of the lubricating oil turbulent which are formed on said facewherein the lubricating oil is to be fed.